JPH09324443A - Control device for construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operability by gradually reducing a flow rate of pressure oil supplied to a hydraulic actuator of a work machine from operation time when an operation lever is returned to a neutral position from an operation position. SOLUTION: When a work machine is driven by supplying pressure oil of a flow rate according to an operation quantity of an operation lever to a hydraulic actuator of the work machine, a soft mode switch is turned on according to its necessity. Next, for example, a flow rate of pressure oil supplied to an arm cylinder is gradually reduced from operation time when an operation lever for an arm is returned to a neutral position from an operation position. Next, a flow rate of the pressure oil becomes zero after a prescribed time from operation time when the operation lever is returned to a neutral position. When the soft mode switch is turned off, practice of soft mode control is released. Therefore, a shock to an operator can be prevented, and durability of a construction machine can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a construction machine.

[0002]

2. Description of the Related Art In a construction machine in which a hydraulic oil of a working machine is supplied with a flow amount of pressure oil corresponding to an operation amount of an operating lever to drive the working machine, the operating lever is conventionally returned to a neutral position. And as shown by the broken line in FIG.
The flow rate of the pressure oil supplied to the hydraulic actuator would be instantly zero.

[0003]

Therefore, when the operating lever is returned to the neutral position, the operator is shocked and the hydraulic equipment is also shocked, which may impair the durability of the construction machine. was there.

[0004]

Therefore, in the present invention, the construction machine is adapted to drive the working machine by supplying the hydraulic actuator of the working machine with a pressure oil having a flow rate corresponding to the operation amount of the operation lever. In, the flow rate of the pressure oil supplied to the hydraulic actuator is gradually reduced from the operation time when the operation lever is returned from the operation position to the neutral position, and after a predetermined time from the operation time when the operation lever is returned to the neutral position. Control means for reducing the flow rate of the pressure oil to zero, and actuating the control means in response to a switch-on operation,
And a switch for releasing the operating state of the control means in response to a switch-off operation.

According to this structure, as shown by the solid line in FIG. 5, the flow rate of the pressure oil supplied to the hydraulic actuator is gradually reduced from the time when the operation lever is returned from the operation position to the neutral position. The flow rate of the pressure oil is reduced to zero after a predetermined time has passed from the time of the operation of returning to the neutral position.

Therefore, the operator is not shocked and the durability of the construction machine is improved.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a control device according to the present invention applied to a power shovel 40. This embodiment has an operation panel OP having a structure as shown in FIG. This operation panel OP has a flexible sheet 1 made of synthetic resin on the panel surface, as shown in the panel layout in FIG. 3 and the sectional view taken along the line AA in FIG. 3 in FIG. It is stretched. This sheet 1 has a light-shielding property, but a switch position mark 21 attached to the appropriate place.
~ 211, lighting display mark 3, character mark and pattern mark
Translucency is imparted to the black.

Push button switches 41 to 41 are provided on the rear side of the sheet 1 at the respective portions marked with marks 21 to 211.
411 is provided, and a light emitting diode 5 is provided on the back surface side of the sheet 1 at each portion marked with a mark 3. A liquid crystal display 6 is provided above the panel.

In the casing 7, an illumination lamp 8 for irradiating each of the above-mentioned translucent marks from the back side of the sheet 1.
And an illumination lamp 9 for illuminating the liquid crystal display 6 from the back side thereof.

The push button switches 41 to 411 are of a type that is turned on only when they are pressed, and are turned on by pressing the portions of the marks 21 to 211 to bend the sheet 1. Table 1 below shows the operation items of these switches 41 to 411 and the contents instructed by the operation.

[0012] The work modes "excavation", "rectification", "fine operation" and "heavy excavation" shown in the table above indicate the basic work types of power shovels, of which "rectification" is for earthmoving work and "Fine operation" means fine operation of the working machine.

The power modes "S", "L" and "H" are control modes for instructing the output of the engine and the output ratio of the hydraulic pump when the engine output is 100. It is The output ratio of the pump is, for example, H = 100% (about 100%), L = 50%, S = 80.
%.

Further, the auto decel means a control mode for reducing the engine speed to a preset low speed when the operator returns the working machine operating lever to the neutral position.

Further, the soft mode is such that, when the working machine operating lever is returned to the neutral position, the oil flowing to the hydraulic actuator of the working machine is not instantaneously shut off, as shown in FIG. It means the control mode to decrease.

The priority mode is a control mode for instructing which of the boom cylinder, arm cylinder and turning motor of the power shovel to increase the amount of oil supplied. .

The swing lock means to lock the upper swing body of the power shovel, and the fan means a fan of a heater.

The signals S1 to S11 shown in FIG. 2 are signals indicating the instruction contents A to K shown in Table 1 above, and these signals are output through the output circuit 12. Also the signal S8,
S9 and S10 are applied to the buzzer 15, the fan 16 and the wiper 17, respectively, and the signal S11 is the illumination lamp 8,
9 and lights (headlights, work lights) 18 are added.

Each of the signals S1, S2, S6, S9, S10 and S11 is a signal having a plurality of bits, and the instruction content is displayed by a combination of the logical levels of the bits.

6 to 17 show the processing procedure of the CPU 11.

In the CPU 11, first, when the power is turned on, that is, when the key switch of the power shovel is turned on, an initial setting process for setting the most standard operation mode of the power shovel is executed. (Step 10
0). That is, the process of setting the content of the work mode counter to 1 and setting the work mode to "excavation", and the process of setting the content of the power mode counter to 1 and setting the power mode to "S". , The auto decel flag is set to "H" and the auto decel mode is set to "ON", the soft mode flag is set to "L" and the soft mode is set to "OFF", and the traveling speed flag is set to "L". To set the traveling speed mode to "LO", to set the content of the priority mode counter to 0 to set the priority mode to "standard", and to set the swing lock flag to "L" to instruct the swing lock. Processing to set the content to "OFF", processing to set the buzzer cancel flag to "L" to set the instruction content for the buzzer cancel to "OFF", and setting the fan flag to "L" to connect to the fan. "OFF" the instruction content
And the process of setting the wiper counter content to 0 and the wiper instruction content to “OFF”,
A process for turning off the contents of the light counter and a process for setting the contents of the illumination / light counter to 0 and turning off the instruction contents for the illumination / light are executed as the initial setting process.

After the initial setting process, the CPU 11 sequentially determines whether or not the push button switches 41, 42, ... 411 are turned on (steps 101, 102 ... 11).
1). When it is determined in step 101 that the switch 41 has been turned on, the work mode process shown in FIG. 7 is executed, and then the procedure proceeds to step 102.

In the operation procedure shown in FIG. 7, first, the soft mode flag is set to "L" to set the soft mode to "OFF".
Processing is executed (step 120), and then processing for adding 1 to the contents of the work mode counter is executed (step 121). Then, it is judged whether the content of the work mode counter is 4, it is judged whether it is 1, and 2
Is determined (steps 122, 1
23 and 124), if the content of the counter is neither 4, 1 nor 2, that is, 3, the process of setting the work mode to "fine operation", and setting the power mode counter to 2 and setting the power mode to "L" And a process for setting the auto decel flag to "L" to set the auto decel mode to "OFF" (step 12).
5).

If it is determined in step 122 that the content of the work mode counter is 4, the content of the work mode counter is set to 0 (step 126), and then the work mode is set to "heavy excavation". The process, the process of setting the content of the power mode counter to 0 and setting the power mode to "H", and the process of setting the auto decel flag to "H" and setting the auto decel mode to "ON" are executed (step 127). ).

Further, when it is determined in step 123 that the content of the work mode counter is 1, processing for setting the work mode to "excavation" and setting the content of the power mode counter to 1 and setting the power mode to " S "processing,
A process of setting the auto decel flag to "H" and turning the auto decel mode to "ON" is executed (step 128).

Furthermore, if it is determined in step 124 that the content of the work mode counter is 2, the process of setting the work mode to "correction" and the content of the power mode counter being 1 are set to the power mode. Is set to "S" and a process of setting the auto decel flag to "L" to set the auto decel mode to "OFF" (step 129).

When the switch 41 is turned on as described above, the power mode and the auto de-selling mode are set to the contents suitable for the work type, and these modes are set to the switch 42. , 4 3 can be changed arbitrarily by turning ON.

That is, step 102 shown in FIG.
When the ON operation of the switch 42 is judged by. As shown in FIG. 8, the content of the power mode counter of the CPU 11 is incremented by 1 (step 130). Then, it is judged whether or not the contents of the counter are 3 and 1 (steps 131 and 132). If the judgment results are both NO, that is, the power mode counter. If the content is 2, power mode "L" is designated (step 133).

If it is determined in step 131 that the content of the power mode counter is 3, the content of the counter is set to 0 (step 134), and then the power is reset.
Mode "H" is instructed (step 135), and if it is determined in step 132 that the content of the counter is 1, power mode "S" is instructed (step 136). ). According to this procedure, the power mode is changed every time the power mode switch 42 is operated.
As described above, the power modes "S", "L" and "H" are the contents 1 and 2 of the power mode counter, respectively.
And 0.

On the other hand, when it is judged in step 103 in FIG. 6 that the auto decel switch 43 is turned on, the auto decel flag is inverted (step 140) as shown in FIG. -It is determined whether the Todecel flag is "H" (step 141).
Then, if it is judged not to be "H", the auto decel "OFF" is instructed (step 142), and if it is judged to be "H", the auto decel "ON" is instructed (step 142). Step 143).

Therefore, when the switch 43 is turned on in the auto decel “ON” state, the auto decel “OF” is selected.
"F" is instructed, and when the switch 43 is turned ON in the auto decel "OFF" state, the auto decel "ON" is instructed.

Next, when it is judged in step 104 in FIG. 6 that the soft mode switch 44 is turned on, as shown in FIG. 10, steps 140 to 14 in FIG.
The steps 150 to 153 according to step 3 are executed, and the soft mode is changed each time the switch 44 is turned on.

That is, when the soft mode "ON" is instructed, as shown by the solid line in FIG. 5, the hydraulic actuator is operated from the time when the operating lever, for example, the arm operating lever 38a is returned from the operating position to the neutral position. The flow rate of the pressure oil supplied to a certain arm cylinder 41 is gradually reduced, and the flow rate of the pressure oil is reduced to zero after a predetermined time has elapsed from the operation time point when the arm cylinder 41 was returned to the neutral position.

On the other hand, when the soft mode "OFF" is instructed, the control contents of the soft mode are not executed.

When the ON operation of the priority mode switch 46 is judged in step 106 shown in FIG. 6, 1 is added to the content of the priority mode counter as shown in FIG. 12 ( Then, it is judged whether or not the contents of the counter are 4, 1 and 2 (steps 171, 172 and 173), and the judgment results are all. If NO, that is, if the content of the priority mode counter is 3, "turn" is instructed.

When it is determined in step 171 that the content of the counter is 4, the content of the counter is set to 0 (step 175) and the priority mode "standard" is designated. (Step 176). Further, when it is determined in step 172 that the content of the counter is 1, the priority mode “boom” is instructed (step 17
7) If the counter content is judged to be 2 in step 173, the priority mode "arm" is designated (step 178).

As mentioned above, the priority mode "standard",
"Boom", "arm" and "turn" correspond to contents 0, 1, 2 and 3 of the priority mode counter, respectively. By changing the contents of this counter by operating the switch 46, an arbitrary priority mode can be designated.

Incidentally, steps 105 and 1 in FIG.
When it is judged that the traveling speed switch 45, the turning lock switch 47 and the buzzer cancel switch 48 are turned on at 07 and 108, as shown in FIG. 11, FIG. 13 and FIG. Steps 140-143
160-163, 180-183 and 1 according to
90 to 193 are executed respectively.

Here, the traveling speed switch 45 is turned on.
The operation when operated will be described.

The traveling speed switch 45 is provided with a hydraulic motor (not shown) for driving the traveling body of the power shovel 40, and the inclination angle of the swash plate is either of "high speed (Hi)" and "low speed (Lo)". It is a switch for switching to an angle.

Therefore, as shown in FIG. 11, when the switch 45 is turned on, the traveling speed flag is inverted to "H" (step 160), and the swash plate tilting of the hydraulic motor is performed. The corner is switched to "high speed (Hi)", and the traveling speed of the traveling body is "high speed (Hi)".
Is set to the speed (YES in step 161, step 163). When the switch 45 is further turned on in this state, the traveling speed flag is inverted to "L" (step 160), and the swash plate tilt angle of the hydraulic motor is changed to "low speed (Lo)". The traveling speed of the traveling body is switched to the "low speed (Lo)" speed (NO in step 161; step 16).
2). Hereinafter, every time the switch 45 is repeatedly turned on, the process of setting the traveling speed of the traveling body to the “high speed (Hi)” speed, and the traveling speed of the traveling body to the “low speed (Lo)” speed are set. The processing to be performed is sequentially repeated.

Next, the operation when the turning lock switch 47 is turned on will be described.

As described above, the swing lock switch 47 is a switch for locking the movement of the upper swing body of the power shovel 40.

Therefore, as shown in FIG. 13, when the switch 47 is turned on, the turning lock flag is inverted to "H" (step 180), and the turning lock function is activated to activate the upper portion. The swing structure is locked (YES at step 181, step 183). When the switch 47 is further turned on in this state, the turning lock flag is inverted to "L" accordingly (step 180), the turning lock function is released, and the movement of the upper turning body is unlocked. (No in step 181; step 182). Hereinafter, every time the switch 47 is repeatedly turned on, the locked state of the upper swing body and the unlocked state of the upper swing body are sequentially repeated.

Next, the operation when the buzzer cancel switch 48 is turned on will be described.

Here, the buzzer cancel switch 48
Is a switch for turning off the ringing of the buzzer 15 which is activated in the warning state, as is clear from the symbol mark on the operation panel OP shown in FIG.

Therefore, as shown in FIG. 14, when the switch 48 is turned on, the buzzer cancel flag is inverted to "H" (step 19).
0), the buzzer cancel function operates, and the operation of the buzzer 15 is turned off (YES in step 191; step 1).
93). When the switch 48 is further turned on in this state, the buzzer cancel flag is set to "L" accordingly.
(Step 190), the buzzer cancel function is released, and the buzzer 15 is activated (turned on) (determined NO in step 191, step 192).
Thereafter, each time the switch 48 is turned on, the operation state of the buzzer 15 and the operation state of the buzzer 15 are sequentially repeated.

Also, steps 109 and 1 in FIG.
When it is determined that the fan switch 49, the wiper switch 410, and the illumination / light switch 411 are turned on by 10 and 111, as shown in FIG. 15, FIG. 16 and FIG. Procedures 200, 206, 210-216 and 220-226 according to 136
Are executed respectively.

The CPU 11 has a function of displaying the processing result of the initialization processing 100 shown in FIG. 6 and the processing results shown in FIGS. 7 to 17.

That is, for example, when "heavy excavation" in the working mode is instructed, the character mark (heavy excavation) shown in FIG. 3 is displayed through the display drive circuit 19 shown in FIG. The light-emitting diode 5 located at the position of () is turned on.
This allows the operator to see that the "heavy excavation" mode is currently instructed.

Further, the CPU 11 inputs the output signals of the sensors 201 to 20n for detecting the engine water temperature, the amount of fuel, the engine oil pressure, etc., and outputs the detection results of these sensors and the above detection results via the display drive circuit 19. The liquid crystal display 6 also displays the information.

Signals S1 ...
S7 is added to the pump controller 30 shown in FIG.

Variable displacement hydraulic pumps 31, 3 shown in FIG.
2 is driven by the engine 33, and the tilt angles of the swash plates 31a and 32a are changed by the swash plate driving servo actuators 34 and 35, respectively.
The discharge flow rate per rotation is changed.

The pressure oil discharged from the pump 31 passes through the arm Lo operation valve 36, a left traveling operation valve, a turning operation valve, and a boom Hi operation valve (not shown), and the arm sill ring 41. Are supplied to a left traveling motor, a turning motor, and a boom cylinder 42, which are not shown.

On the other hand, the pressure oil discharged from the pump 32 is passed through the arm Hi operation valve 37, the right traveling operation valve, the bucket operation valve, and the boom Lo operation valve (not shown). 41, a right running motor (not shown), a bucket cylinder 43, and a boom cylinder 42, respectively.

The arm PPC valve 38 is provided with the arm Lo operating valve 3 when the lever 38a is operated in the direction of arrow E.
Pilot pressure oil is supplied to the pilot port 36a of No. 6 and the pilot port 3 of the Hi operation valve 37 for the arm is provided.
The pilot pressure oil is supplied to 7a through the normally open solenoid valve 39.

When pilot pressure oil acts on the pilot ports 36a and 37a, the arm Lo operation valve 36 and the arm
The arm Hi operation valve 37 supplies the pressure oil discharged from the pumps 31 and 32 to the extension side cylinder chamber of the arm cylinder 41, and operates the arm 44 to the rear side of the vehicle body.

At the time of excavation, the arm 4 is placed on the rear side of the vehicle body.
4 is activated.

On the other hand, when the lever 38a of the PPC valve 38 is operated in the direction of arrow F, pilot pressure oil is supplied to the pilot port 36b and the arm of the arm Lo operating valve 36.
The hydraulic oil supplied to the pilot ports 37b of the Hi control valve 37 for the cylinders, respectively, and the pressure oil discharged from the pumps 31 and 32 is supplied to the compression side cylinder chamber of the arm cylinder 41. As a result, the arm 44 is driven to the front side of the vehicle body. As is well known, during the dumping work, the arm 44 is driven to the front side of the vehicle body.

For the traveling operation valve, the turning operation valve and the like described above, different PPC valves having the same functions as the PPC valve 38 are also used.

The solenoid valve 39 is closed by a signal output from the pump controller 30. When the solenoid valve 39 is closed, the arm Hi operating valve 3
Since the pilot port 37a of 7 and the PPC valve 38 are closed, when the lever 38a of the valve 38 is operated in the E direction, only the pressure oil discharged from the pump 31 is supplied to the arm L.
It is supplied to the arm cylinder 41 via the operation valve 36.

19A and 19B are PPC valves 3 when the valve 39 is open and closed, respectively.
8 Stroke amount of lever 38a attached to 8 and pump 3
The relationship with the discharge flow rate Q (l / min) of 1, 32 is shown.

As is clear from the figure, the two pumps 3
When one of the pumps 32 is separated and the discharge oil of only one pump 31 is supplied to the cylinder 41 as compared with the case where the discharge oils of 1 and 32 are supplied together to the arm cylinder 41, the flow rate changes. The amount of change in the amount of reverse stroke to the amount is large.

This means that the minute control function of the lever 38a is improved. After all, valve 39
Has a function of separating one pump 32 from the hydraulic pressure supply path for the arm 44 when the lever 38a is operated in the E direction.

The pilot pressure oil is also supplied to the TVC valve 51. The pilot pressure oil controlled by the TVC valve 51 is supplied to the servo actuator 34 via the CO valve 52 and the NC valve 53, and to the servo actuator 35 via the CO valve 54 and the NC valve 55. Supplied.

A hydraulic system including the valves 51 to 55 is known, for example, from Japanese Patent Laid-Open No. 61-81587.

The TVC valve (torque variable control) 51 is provided to keep the combined absorption horsepower of the pumps 31, 32 constant. That is, the valve 51 inputs the discharge pressures P1 and P2 of the pumps 31 and 32, and as shown by the characteristics A1, A2 and A3 in FIG.
+ P2) / 2 and the combined discharge flow rate Q of the pumps 31 and 32 are constant, that is, the combined absorption horsepower is approximately constant, and the swash plate 3 is interposed via the servo actuators 34 and 35.
The tilt angles of 1a and 32a are controlled.

This TVC valve 51 has a controller 30
A characteristic selection signal is further added, and one of the characteristics A1, A2 and A3 is selectively set by this signal.

The CO valves 52 and 54 are respectively the pump 3
The discharge pressures of 1 and 32 are input, and when these discharge pressures exceed a predetermined cutoff pressure, the discharge pressures of the valves 52 and 54 are rapidly reduced, and the swash plates 31a and 32a are set to the minimum position. It acts to return.

When the pumps 31 and 32 are regarded as one pump, the CO valves 52 and 54 rapidly reduce the discharge flow rate Q of the pumps along the cutoff line G as shown in FIG.

The CO valves 52 and 54 are normally closed solenoid valves 5.
It is connected to the pump 50 via 6. When the solenoid valve 56 is not energized, the CO valve 52,
54 performs the above-mentioned cutoff operation. When the solenoid valve 56 is closed by the output signal of the controller 30, pilot pressure acts on the CO valves 52 and 54 and the cutoff function is lost, so that the discharge pressures P1 and P2 of the pumps 31 and 32 are Release of a relief valve not shown
It is possible to raise the pressure to the maximum.

When the solenoid valve 56 is closed, the cutoff release switch 70 is operated by the operator.

The NC valve 53 serves to reduce the output pressure of the valve 53 when all the operation valves connected to the pump 31 are in the neutral state.

That is, under the neutral condition of each of the above-mentioned operating valves, the flow rate of the Carryover is input as a signal to a jet sensor (not shown), and thereby two pressures having a pressure difference are generated in the sensor. The NC valve 53 inputs these two pressures and acts to reduce the output pressure as the difference between the two pressures increases.

The output pressure of the NC valve 53 is reduced by the swash plate 3
The tilt angle of 1a is reduced. Therefore, the NC valve 53 has a function of reducing the discharge flow rate of the pump 31 in the neutral state of each operation valve to prevent energy loss.

The NC valve 55 also has a similar function to the pump 32.

The engine 33 shown in FIG. 1 is provided with a fuel injection pump 61 and a governor 62. Governor 6
The second fuel control lever 62a is driven by the motor 63, and the driving position of the lever 62a is detected by the sensor 64.

The throttle amount setting device 65 includes a dial 65
a and a potentiometer rotated by this dial 65a
And 65b. Electric governor controller 6
0 compares the first throttle signal output from the setting device 65 with the second throttle signal output from the pump controller 30, and based on the smaller one of them, the motor 63 is set. To drive.

The governor 62 controls the output torque of the engine 33 according to the characteristics shown in FIG.

Regulation line l1 in FIG.
Is set when the maximum target engine speed is instructed by the first throttle signal or the second throttle signal, and is regulated as the target engine speed instructed by the first or second throttle signal becomes smaller.
The operation lines l2, l3, ... Are sequentially determined. That is,
The governor 62 has a function of a so-called “all speed governor”.

The specific operation of this embodiment will be described below. In the following, it is assumed that the throttle amount setter 65 is set to the maximum position. Table 2 below summarizes the main actions of this embodiment. Work mode signal S input to the pump controller 30
1 is "heavy excavation", "drilling", "rectification" as described above
Indicate one of the work modes of “fine operation” and “fine operation”.

Assuming that the "heavy excavation" mode is instructed, the contents of the power mode signal S2 output from the operation panel OP are "as shown in step 127 of FIG. "H" and the content of the auto decel signal S3 is "ON"
become.

Therefore, the controller 30 has a power mode.
A process of setting the output horsepower of the engine 33 to the high horsepower PS-H and a process of setting the rotation speed of the engine 33 to the high rotation speed NA are executed based on the content "H" of the command.

That is, the equal horsepower characteristic A shown in FIG.
A signal is applied to the TVC valve 51 to set 1, and a second throttle signal indicating the maximum throttle amount is applied to the governor controller 60.

As a result, the combined absorption torque of the pumps 31, 32 exhibits a magnitude according to the characteristic AH in FIG.

Further, the second throttle signal indicating the maximum target rotational speed NA 'is compared with the output signal of the throttle amount setter 65 in the governor controller 60.

The output signal of the setter 65 is currently set to a value indicating the maximum target engine speed NA '. Therefore, in this case, the controller 60 sets the maximum target engine speed NA' to the maximum target engine speed NA '. A corresponding motor drive signal is applied to the governor drive motor 63. As a result, the motor 63 operates the fuel control lever 62a so that the maximum speed regulation line IA is set. As a result, the output torque of the engine 33 and the pump 3
The combined absorption torques of 1 and 32 will match at the PH point (maximum horsepower point).

Thus, when the heavy excavation mode is instructed, the output horsepower of the engine 33 is automatically set to PS-H (horsepower at the maximum horsepower point) and the engine speed is automatically set to NA.

On the other hand, the pump controller 30 operates the levers which are attached to the respective PPC valves by the lever neutrality detection sensor 71 based on the content "ON" of the auto decel signal S3.
Only when it is detected that all of the levers 38a of the arm PPC valve 38 are shown in the drawing, that is, the power shovel 40
The decel signal is applied to the governor controller 60 only when it is detected that the task is idle.

Based on the deceleration signal, the controller 60 sets the target rotation speed of the engine 33 from the maximum target rotation speed NA 'set by the second throttle signal until then to the second rotation speed.
The process of changing to the value ND 'shown in FIG. 1 (a) is executed.

As a result, the governor motor 63 is operated so that the regulation line ID shown in FIG. 21 (a) is set, and as a result, the engine speed is greatly reduced.

When the power mode "H" is set in the heavy excavation mode as described above, engine noise and fuel consumption during non-work become extremely large. Since the decel signal significantly reduces the engine speed during the non-working time, noise and fuel consumption during the non-working time can be reduced.

When the heavy excavation mode is instructed, the pump controller 30 also serves to turn off the pump separation function (see Table 2), that is, the energizing signal to the normally open solenoid valve 39. Is output, and the normally open state of the valve 39 is continued.

In this case, as described above, the pumps 31, 3
Arm cylinder 4 by pressure oil discharged from both
1 is driven, whereby a force suitable for heavy excavation can be applied to the arm 41.

On the other hand, the controller 30 performs the cutoff operation by the CO valves 52 and 54 when the heavy excavation mode is instructed.
Turn on. That is, the normally closed solenoid valve 56 does not output an energizing signal, which causes the CO valves 52 and 53 to perform the above-described cutoff operation.

As described above, when the heavy excavation mode is instructed by the operation panel OP, the power mode H suitable for the heavy excavation work is selected, and the horsepower of the engine is PS-H.
And the number of rotations is automatically set to NA.

Further, the pump separation function, the cutoff function, and the auto deceleration function are "OFF" and "ON", respectively.
And "ON" are automatically set.

The above functions are shown in the thick line frame in Table 2 above.

Next, the case where the "excavation mode" is instructed on the operation panel OP will be described.

In this case, as shown in step 128 in FIG. 7, the power mode "S" is selected on the operation panel OP and the auto decel "ON" is selected. Therefore, the controller 30 outputs a signal for obtaining the equal horsepower characteristic A2 shown in FIG. 20 to the TVC valve 51, and also outputs a second throttle signal indicating the target engine speed NB '. Give to.

Since the rotational speed NB 'is smaller than the set rotational speed NA' of the setter 65, the controller 60 sends the motor drive signal corresponding to the target engine rotational speed NB 'to the motor 63. Governor 62, which gives governor 62 FIG. 21 (b).
Set the regulation line 1B shown in.

Therefore, the combined absorption torque of the pumps 31, 32 and the output torque of the engine 33 match at Ps' point, and as a result, the engine 33 outputs the output horsepower PS-S.
(<PS-H), the engine is operated at the rotational speed NB.

That is, the operating state is suitable for normal excavation.

Since the instruction contents for the pump separation function, the cutoff function and the auto decel function are the same as those for heavy excavation, the description thereof will be omitted.

In Table 2, the contents automatically set at the time of instructing the excavation mode are shown in the bold line frame.

When the "rectification mode" is instructed on the operation panel OP, the power mode S having the same contents as the power mode S at the time of instructing the excavation mode is automatically set, TVC valve 5
The same process as described above is executed for 1 or the engine 33.

On the other hand, when the "rectification mode" is instructed, as shown in step 129 of FIG.
FF ”will be set. Therefore, the control
Even if the lever neutral position detection sensor 71 detects the neutral state, the laser 30 outputs the deceleration signal to the governor controller 60.
Do not output to.

The reason for not performing the decelling operation in the rectifying mode is as follows. That is, during the adjustment work, the working machine operation lever is frequently returned to the neutral position. Therefore, if the engine speed is reduced by the deceleration process each time, proper work cannot be performed.

On the other hand, when the adjustment mode is instructed, both the pump separation function and the cutoff function are set to "ON", as shown in the thick line frame in Table 2. That is, the pump controller 30 applies an urging signal to the normally open solenoid valve 39 to close the valve 39, whereby the PPC valve 38 is closed.
When the lever 38a is operated in the E direction,
The pressure oil discharged only from the pump 31 when the arm cylinder 41 is operated in a direction to extend the arm cylinder 41
Will act on. That is, the arm cylinder 41
One of the pumps 32 is separated from the cylinder 41 when the cylinder is extended.

When the lever 38 is operated in the F direction, the oil discharged from both the pump 31 and the pump 32 causes the cylinder 41 to retract and operate.

After all, the pump separation “ON” process is performed by the arm 4
4 should be operated in the counterclockwise direction (excavation work direction) with the discharge pressure oil of the pump 31 only, and should be operated in the clockwise direction (dump work direction) with the combined pressure oil of the two pumps 31, 32. This means that the finishing surface accuracy at the time of adjustment is improved without reducing the work amount.

Further, since the pump 32 is connected to the bucket cylinder 43 via the bucket operation valve (not shown), if the separation "ON" process is performed, the PPC
When the lever 38a of the valve 38 is operated in the E direction, the pump 31 operates the arm cylinder 41 and the pump 32 operates the bucket cylinder.

Therefore, since there is no load interference between the arm cylinder 41 and the bucket cylinder 43, the accuracy of the finished surface at the time of alignment is improved.

The cut-off “ON” processing has been described above, and therefore its explanation is omitted.

When the fine operation mode is instructed on the operation panel OP, the power mode "L" is set on the operation panel OP as shown in step 125 of FIG. Therefore, the pump controller 30 performs the following processing to obtain the power mode "L" shown in the column of "fine operation mode" in Table 2.

That is, a signal for obtaining the equal horsepower characteristic A3 of FIG. 20 is given to the TVC valve 51, and the pump absorption torque characteristic AL shown in FIG. 21 (c) is set.

On the other hand, the second throttle signal indicating the target rotation speed Nc 'is output to the governor controller 60, whereby the controller 60 sets the regulation line lc shown in FIG. Governor Motor 6
Drive 3

As a result, the combined absorption torque of the pumps 31 and 32 and the output torque of the engine 33 match at the point PL ", whereby the engine 33 outputs the output horsepower PS-L.
2 (<PS-S <PS-H) and the engine speed is Nc.

Pump separation, cut-off and off
The Todecel is the same as in the case of the adjustment mode.

As shown in Table 2, in this embodiment, when each work mode is designated by the operation panel OP, a power mode and a pump separation function suitable for the work mode are provided. The cut-off function and the auto decel function are automatically set, but it is naturally possible to add functions other than these functions, such as the software function and the priority function, to the contents of the automatic setting. It is also possible to manually set any of these functions except the pump separation function.

That is, as shown in FIGS. 8 and 9, the type of power mode and the ON / OFF of the auto decel.
Can be arbitrarily selected manually, and the cutoff function can be arbitrarily released by operating the cutoff release button opening switch 70 shown in FIG. Note that PS-L1 (> PS-L2) shown in Table 2 is the horsepower at the matching point PL in FIG. 21 (b).

By the way, when the pump absorption characteristic AH shown in FIG. 21 is set, it may be difficult to match the pump absorption torque and the engine torque. Therefore,
When the pump is driven at the maximum horsepower point PH, it is preferable to set the characteristic AH 'instead of the characteristic AH as illustrated by the dotted line in the figure.

This characteristic AH 'cannot be obtained by the TVC valve 51, but can be obtained as follows, for example.

That is, the pressure P1 of the pumps 31, 32,
P2 is detected by each pressure sensor, and the engine 33
If the rotation speed sensor 72 detects the rotation speed N of the
Since H'is a monotonically increasing function with the engine speed N as a variable, the pump 31 for obtaining the absorption torque according to the characteristic AH 'from the average value (P1 + P2) / 2 and N of the pressures P1 and P2. , 32 can be obtained. Therefore, the swash plates 31a, 3a are adjusted so as to have the tilt angle.
By controlling 2a, the characteristic AH 'can be obtained. In addition,
Since ON / OFF of each function in Table 2 above is set according to the model of the construction machine to which it is applied, it is not limited to the contents of the above table.

In the above embodiment, one deceleration speed ND 'is set as the deceleration speed when the auto decel is turned on. However, the same setting device as the rotation speed setting device 65 shown in FIG. It is also possible to configure so that a desired deceleration speed can be set by using such a changeover switch.

Further, the cutoff release switch 70 is provided.
Since the cutoff release by is usually required during heavy excavation, while the switch 70 is being pressed,
It is also possible to cause the layers 30 and 60 to execute the following processing.

A. Regardless of which work mode or power mode is selected, the work mode is changed to “heavy excavation mode”.
Power mode, and the power mode of "heavy excavation mode power"
Switch to "Mode H" respectively.

B. The set pressure of the main relief valves connected to the pumps 31 and 32 is changed from a normal set pressure to a set pressure higher by about 10 to 20 kg / cm 2 than the set pressure. The set pressures of the CO valve 52,
Naturally, it is set higher than the cutoff pressure of 54.

In this case, a relief pressure valve of variable set pressure is used, and switching of the relief valve is performed by, for example, a solenoid valve (not shown) controlled by the controller 30 acting on the relief valve. It is done by changing. Of course, it is also possible to use a relief valve capable of changing the set pressure by directly applying an electric signal.

C. Even if the switch 70 is continuously pressed, after several seconds (for example, about 7 to 10 seconds), all the functions are automatically returned to the states before the switch operation.

[0131]

As described above, according to the present invention, the flow rate of the pressure oil supplied to the hydraulic actuator is gradually reduced from the time when the operation lever is returned from the operation position to the neutral position, so that the neutral position is neutralized. Since the flow rate of the pressure oil is reduced to zero after a predetermined time has elapsed from the time when the operation was returned to the position, it is possible to prevent the operator from being shocked and to improve the durability of the construction machine.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a control device according to the present invention.

FIG. 2 is a block diagram showing a configuration of an operation panel.

FIG. 3 is a front view showing a panel layout of an operation panel.

FIG. 4 is a sectional view taken along line AA in FIG.

FIG. 5 is an explanatory diagram of a soft mode process which is a control content of the control device according to the present invention.

FIG. 6 is a flowchart showing a processing procedure of the CPU shown in FIG.

FIG. 7 is a flowchart showing a processing procedure of the CPU shown in FIG.

FIG. 8 is a flowchart showing the processing procedure of the CPU shown in FIG.

9 is a flowchart showing a processing procedure of the CPU shown in FIG.

10 is a flow chart showing the processing procedure of the CPU shown in FIG.

FIG. 11 is a flowchart showing a processing procedure of the CPU shown in FIG.

FIG. 12 is a flowchart showing a processing procedure of the CPU shown in FIG.

FIG. 13 is a flowchart showing a processing procedure of the CPU shown in FIG.

FIG. 14 is a flowchart showing a processing procedure of the CPU shown in FIG.

15 is a flow chart showing the processing procedure of the CPU shown in FIG.

16 is a flowchart showing a processing procedure of the CPU shown in FIG.

FIG. 17 is a flowchart showing the processing procedure of the CPU shown in FIG. 1.

FIG. 18 is a characteristic diagram showing the action of the governor.

FIG. 19 is an explanatory diagram of a pump separation function.

FIG. 20 is a characteristic diagram showing the action of the TVC valve.

FIG. 21 is a characteristic diagram showing actions during various works.

[Explanation of symbols]

OP ... Operation panel, 41-411 ... Pushbutton switch, 11 ... CP
U, 30 ... Pump controller, 31, 32 ... Constant capacity hydraulic pump, 33 ... Engine, 38 ... PPC valve, 51 ...
TVC valve, 60 ... electric governor controller, 61 ... fuel injection pump, 62 ... governor, 63 ... motor, 65 ... throttle dial.

Claims (1)

[Claims] 1. A construction machine in which a hydraulic oil of a working machine is supplied with a flow amount of pressure oil according to an operation amount of the operating lever to drive the working machine, wherein the operating lever is moved from an operating position to a neutral position. A control means for gradually reducing the flow rate of the pressure oil supplied to the hydraulic actuator from the time of the operation returned, and zeroing the flow rate of the pressure oil for a predetermined time after the operation time of returning to the neutral position. A control device for a construction machine, comprising: a switch that activates the control means in response to a switch-on operation, and that releases the operating state of the control means in response to a switch-off operation.